Transmission electron micrograph of an axodendritic synapse from a rat's central nervous system. A nerve enters the field at the upper right. Its myelin sheath terminates and its axon expands into a terminal bouton closely applied to the surface of a large dendrite at the left. The nerve terminal is filled with synaptic vesicles. The synaptic complex (at the arrow) is of relatively limited extent, but similar local membrane specializations are probably present in other planes of section.